Method for driving plasma display panel and plasma display device

ABSTRACT

A plasma display device includes a plasma display panel and a driver unit driving the plasma display panel. The plasma display panel includes a first plate on which a sustain electrode and a scan electrode, a dielectric layer, an address electrode extending in a direction intersecting with the sustain electrode, and a protective layer are sequentially stacked and a second plate disposed to face the first plate via a discharge space. On the second plate, a barrier rib extending in the direction intersecting with the sustain electrode is formed. One edge part of the address electrode lies on the barrier rib and the other edge part of the address electrode lies on the discharge space. During an address period, the driver unit applies a scan pulse operating as an anode to the scan electrode and applies an address pulse operating as a cathode to the address electrode. This makes it possible to prevent erroneous discharge.

CROSS-REFERENCE TO THE RELATED APPLICATIONS

This application is the U.S. National Stage application claiming thebenefit of prior filed International Application No. PCT/JP2007/000803,filed on Jul. 27, 2007, the entire contents of which are incorporatedherein by reference.

TECHNICAL FIELD

The present invention relates to a plasma display panel driving methodand a plasma display device.

BACKGROUND ART

A plasma display panel (PDP) is formed by adhering two glass plates (afront glass plate and a back glass plate) each other, and displays animage by generating discharge light in a space (discharge space) formedbetween the glass plates. A cell corresponding to a pixel in the imageis of a self-luminescence type and coated with phosphors emitting red,green, and blue visible light under ultraviolet rays generated bydischarge.

In general, the back glass plate has barrier ribs coated with theabove-described phosphors, and the surface of the front glass plate iscovered with a protective layer protecting a dielectric layer fromdischarge. Incidentally, in order to make discharge to occur easily, theprotective layer is formed of a material having a high emission propertyof emitting secondary electrons by a collision with a positive ion. Inthe PDP, in order to display an image with a multiple gradation, a fieldfor displaying one frame includes a plurality of subfields eachincluding a reset period, an address period, and a sustain period, forexample.

A PDP with a three-electrode structure having a sustain electrode, ascan electrode, and an address electrode displays an image by makingsustain discharge occur between the sustain electrode and the scanelectrode during a sustain period. A cell in which the sustain dischargeis made to occur (a cell to be lit) is selected by making addressdischarge occur selectively between the scan electrode and the addresselectrode during an address period.

In recent years, a PDP in which three electrodes, a sustain electrode, ascan electrode, and an address electrode, are disposed on a front glassplate has been proposed (refer to, for example, Patent Document 1). Forexample, in this type of PDP, a negative pulse is applied to the scanelectrode and a positive pulse is applied to the address electrode inorder to make address discharge occur. Incidentally, in this type ofPDP, the sustain electrode includes an X bus electrode and an Xtransparent electrode provided in each cell, and the scan electrodeincludes a Y bus electrode and a Y transparent electrode provided ineach cell. In addition, the Y transparent electrodes of two cellsadjacent to each other along the orthogonal direction of the addresselectrode are adjacent to each other with the address electrode inbetween.

In two Y transparent electrodes adjacent to each other with the addresselectrode in between, when address discharge is made to occur betweenone Y transparent electrode and the address electrode, there is apossibility that erroneous discharge occurs between the other Ytransparent electrode and the address electrode. In order to prevent theerroneous discharge, a PDP has been proposed in which, in two Ytransparent electrodes adjacent to each other with an address electrodein between, the distance between one Y transparent electrode and theaddress electrode is made shorter than the distance between the other Ytransparent electrode and the address electrode (refer to, for example,Patent Document 2).

Patent Document 1: Japanese Unexamined Patent Application PublicationNo. 2005-116508 Patent Document 2: Japanese Unexamined PatentApplication Publication No. 2006-302866 DISCLOSURE Problems to be Solved

In a PDP having three electrodes on a front glass plate, two cellsadjacent to each other along the orthogonal direction of an addresselectrode are separated from each other by a barrier rib extending inthe direction in which the address electrode extends. However, since thebarrier rib acts as part of a dielectric layer, an electric field isgenerated between a Y transparent electrode and an address electrodewhen a voltage is applied between the address electrode and a scanelectrode (the Y transparent electrode), the Y transparent electrodebeing adjacent to the address electrode with the barrier rib in between.For example, in the PDP of Patent Document 2, when a negative pulse isapplied to the scan electrode (the Y transparent electrode) and apositive pulse is applied to the address electrode in order to makeaddress discharge occur, an electric field is generated from the addresselectrode in each of the two Y transparent electrodes adjacent to eachother with the address electrode in between. As a result, in cells onboth sides of the address electrode, when address discharge is made tooccur in one of the cells, there is a possibility that, in the othercell, a positive ion being in the discharge space is drawn to the Ytransparent electrode and collides with the protective layer on the Ytransparent electrode. In this case, in the other cell, there is apossibility that secondary electrons are emitted from the protectivelayer on the Y transparent electrode, and erroneous discharge is made tooccur.

A proposition of the present invention is to prevent erroneous dischargein a PDP having three electrodes on a front glass plate.

Means for Solving the Problems

A plasma display device includes a plasma display panel and a driverunit driving the plasma display panel. In addition, the plasma displaypanel includes a first plate on which a sustain electrode and a scanelectrode being adjacent to each other and plurally disposed, adielectric layer, an address electrode extending in a directionintersecting with the sustain electrode, and a protective layer aresequentially stacked, and a second plate disposed to face the firstplate via a discharge space. Furthermore, on the second plate, a barrierrib extending in the direction intersecting with the sustain electrodeis formed. Incidentally, one edge part of the address electrode lies onthe barrier rib and the other edge part of the address electrode lies onthe discharge space. Moreover, one field for displaying one frameincludes a plurality of subfields each having an address period. Forexample, during the address period, the driver unit applies a scan pulseoperating as an anode to the scan electrode and applies an address pulseoperating as a cathode to the address electrode.

According to the present invention, it is possible to prevent erroneousdischarge in a PDP having three electrodes on a front glass plate.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view showing an embodiment of thepresent invention.

FIG. 2 is an exploded perspective view showing the details of aprincipal portion of a PDP shown in FIG. 1.

FIG. 3 is an explanatory diagram of a principal portion of the PDP shownin FIG. 2.

FIG. 4 is a sectional view of the PDP shown in FIG. 3 taken on the lineA-A′.

FIG. 5 is an explanatory diagram showing an example of the configurationof a field for displaying an image of one frame.

FIG. 6 is a waveform diagram showing an example of discharge operationof a subfield shown in FIG. 5.

FIG. 7 is a block diagram showing an outline of a circuit unit shown inFIG. 1.

FIG. 8 is an explanatory diagram of a principal portion of a PDP in amodified example of the present invention.

FIG. 9 is a sectional view of the PDP shown in FIG. 9 taken on the lineA-A′.

FIG. 10 is a sectional view of a principal portion of a PDP in anothermodified example of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENT

Hereinafter, an embodiment of the present invention will be described byusing the drawings.

FIG. 1 shows an embodiment of the present invention. A plasma displaydevice (hereinafter also referred to as a PDP device) includes a plasmadisplay panel 10 (hereinafter also referred to as a PDP) in the form ofa rectangular plate, an optical filter 20 provided on that side of thePDP 10 where an image display surface 16 is present (where light isoutput), a front case 30 disposed on that side of the PDP 10 where theimage display surface 16 is present, a rear case 40 and a base chassis50 which are disposed on that side of the PDP 10 where a back surface 18is present, a circuit unit 60 for driving the PDP 10, the circuit unit60 attached to that side of the base chassis 50 which faces the rearcase 40, and a double-faced adhesive sheet 70 for adhering the PDP 10 tothe base chassis 50. The circuit unit 60 is represented as a boxindicated by dashed lines because the circuit unit 60 is made up of aplurality of parts.

The PDP 10 is made up of a front plate part 12 forming the image displaysurface 16 and a back plate part 14 facing the front plate part 12.Between the front plate part 12 and the back plate part 14, a dischargespace (cell), not illustrated, is formed. The front plate part 12 andthe back plate part 14 are formed of a glass plate, for example. Theoptical filter 20 is adhered to protection glass (not shown) fixed overan opening part 32 of the front case 30. Incidentally, the opticalfilter 20 may have the function of blocking electromagnetic waves.Moreover, instead of being adhered to the protection glass, the opticalfilter 20 may be directly adhered to that side of the PDP 10 where theimage display surface 16 is present.

FIG. 2 shows the details of a principal portion of the PDP 10 shown inFIG. 1. An arrow D1 in the drawing represents a first direction D1, andan arrow D2 represents a second direction D2 orthogonal to the firstdirection D1 in a plane parallel to the image display surface.

The front plate part 12 has an X bus electrode Xb and a Y bus electrodeYb formed parallel on a glass base FS (a first plate) (in the drawing,on the underside thereof) along the first direction D1 and formedalternately along the second direction D2 so as to make discharge occurrepeatedly. To the X bus electrode Xb, an X transparent electrode Xtextending in the second direction D2 from the X bus electrode Xb to theY bus electrode Yb is coupled. Moreover, to the Y bus electrode Yb, a Ytransparent electrode Yt extending in the second direction D2 from the Ybus electrode Yb to the X bus electrode Xb is coupled.

Here, the X bus electrode Xb and the Y bus electrode Yb are opaqueelectrodes formed of a metal material or the like, and the X transparentelectrode Xt and the Y transparent electrode Yt are transparentelectrodes allowing light to pass therethrough, the transparentelectrodes formed of a film of ITO or the like. In addition, a sustainelectrode XE is made up of the X bus electrode Xb and the X transparentelectrode Xt, and a scan electrode YE is made up of the Y bus electrodeYb and the Y transparent electrode Yt. Incidentally, the transparentelectrodes Xt and Yt are sometimes disposed on the entire surfacebetween the bus electrodes Xb and Yb to which the transparent electrodesXt and Yt are coupled, respectively, and the glass base FS. Furthermore,an electrode into which the bus electrodes Xb and Yb are integratedtogether may be formed of the same material (a metal material or thelike) as the bus electrodes Xb and Yb in place of the transparentelectrodes Xt and Yt.

The electrodes Xb, Xt, Yb, and Yt are covered with a dielectric layerDL1. For example, the dielectric layer DL1 is a silicon dioxide film (afilm of SiO₂, a film of silicon dioxide) formed by CVD. In addition, onthe dielectric layer DL1 (in the drawing, on the underside thereof), aplurality of address electrodes AE extending in the orthogonal direction(the second direction D2) of the bus electrodes Xb and Yb are provided.As described above, the PDP of this embodiment includes three electrodes(the electrodes XE, YE, and AE) in the front plate part 12.

Moreover, the address electrodes AE and the dielectric layer DL1 arecovered with a protective layer PL. For example, in order to makedischarge more likely to occur, the protective layer PL is formed of afilm of MgO having a high emission property of emitting secondaryelectrons by a collision with a positive ion. As described above, inthis embodiment, on the glass base FS, the sustain electrode XE and thescan electrode YE formed parallel to each other, the dielectric layerDL1, the address electrodes AE extending in the orthogonal direction ofthe sustain electrode XE, and the protective layer PL are sequentiallystacked.

The back plate part 14 facing the front plate part 12 via a dischargespace DS has, on a glass base RS (a second plate), barrier ribs BRextending in the direction (the second direction D2) orthogonal to thebus electrodes Xb and Yb and formed parallel to one another.Incidentally, the barrier ribs BR each have a central axis RC2 in aposition off a central axis RC of the address electrode AE as viewedfrom a direction perpendicular to the glass base FS, and, in partthereof, face the address electrode AE. The barrier ribs BR form theside walls of a cell. Furthermore, on the side surfaces of the barrierribs BR and on the glass base RS between the barrier ribs BR adjacent toeach other, phosphors PHr, PHg, and PHb emitting red (R), green (g), andblue (B) visible light as a result of being excited by ultraviolet raysare applied.

One pixel of the PDP 10 is made up of three cells emitting red, green,and blue light. Here, one cell (a pixel of one color) is formed in thedischarge space DS defined by the bus electrodes Xb and Yb and thebarrier ribs BR. As described above, the PDP 10 is formed by arrangingthe cells for displaying an image in a matrix and arranging a pluralityof types of cells alternately, the cells emitting light of differentcolors. Though not shown in the drawing, the cells formed along the buselectrodes Xb and Yb form a display line.

The PDP 10 is formed by adhering the front plate part 12 and the backplate part 14 each other in such a way that the protective layer PL andthe barrier ribs BR are brought into contact with each other andencapsulating discharge gas such as Ne or Xe in the discharge space DS.

FIG. 3 shows a principal portion of the PDP 10 viewed from the imagedisplay surface side (the upper side of FIG. 2). Incidentally, FIG. 3shows a state of the electrodes Xb, Xt, Yb, Yt, and AE and the barrierribs BR viewed from the image display surface side. The meaning of thearrows in the drawing is the same as that of FIG. 2 described above.

As viewed from the image display surface side, a cell C1 is formed in aregion defined by the bus electrodes Xb and Yb and the barrier ribs BR,and the discharge space DS of each cell C1 is formed between the barrierribs BR adjacent to each other. In addition, each address electrode AEfaces, in part thereof, one of the barrier ribs BR (in the drawing, theleft one) forming the discharge space DS of the cell C1 corresponding tothe address electrode AE. One edge part EG1 of the address electrode AEalong the second direction D2 lies on the barrier rib BR, and the otheredge part EG2 lies on the discharge space DS. In other words, as viewedfrom the image display surface side, the barrier rib BR is provided in aposition where the barrier rib BR has a central axis RC2 in a positionoff a central axis RC of the address electrode AE (in the drawing, aposition off a central axis RC leftward), and part thereof overlaps theaddress electrode AE.

That is, part of the address electrode AE is disposed in such a way asto stick out from the barrier rib BR toward the transparent electrode Ytcorresponding to the address electrode AE (in the drawing, thetransparent electrode Yt located on the right side of the addresselectrode AE). As a result, by applying a voltage between the addresselectrode AE and the transparent electrode Yt, it is possible to makeaddress discharge occur in the discharge space DS of a particular cellC1 (hereinafter also referred to as a selection cell). At this time, thebarrier rib BR also acts as part of the dielectric layer, and anelectric field between the address electrode AE and the transparentelectrode Yt is generated in the discharge space DS.

Incidentally, in two transparent electrodes Yt adjacent to each otherwith the address electrode AE in between, part of the address electrodeAE is disposed in such a way as to stick out from the barrier rib BRonly toward one of the transparent electrodes Yt (in the drawing,rightward). As a result, when address discharge is made to occur betweenthe address electrode AE and the transparent electrode Yt of theselection cell C1 (during an address period), it is possible to reducethe possibility that erroneous discharge occurs in a cell C1(hereinafter also referred to as a non-selection cell) adjacent to theselection cell C1.

Moreover, the transparent electrode Xt and the transparent electrode Ytare disposed in such a way that the ends SD1 and SD2 face each other. Asa result, during a sustain period SUS of FIG. 6, which will be describedlater, by applying a voltage between the transparent electrode Xt andthe transparent electrode Yt, it is possible to make sustain dischargeoccur in the discharge space DS of the particular cell C1.

FIG. 4 shows the cross-section of the PDP 10 taken on the line A-A′ ofFIG. 3. The meaning of the arrows in the drawing is the same as that ofFIG. 2 described above. In this embodiment, the discharge spaces DSadjacent to one another in the first direction D1 are separated from oneanother by the barrier ribs BR. In addition, as described above, part ofthe address electrode AE is disposed in such a way as to stick out fromthe barrier rib BR only toward the transparent electrode Ytcorresponding to the address electrode AE. Accordingly, the protectivelayer PL on the address electrode AE is exposed only in the dischargespace DS on the transparent electrode Yt side (in the drawing, on theright side), the transparent electrode Yt corresponding to the addresselectrode AE.

In this embodiment, in order to make address discharge occur in thedischarge space DS of the selection cell C1, as shown in FIG. 6, whichwill be described later, a scan pulse SPL operating as an anode isapplied to the scan electrode YE, and an address pulse APL operating asa cathode is applied to the address electrode AE. That is, in thisembodiment, address discharge is made to occur by making the addresselectrode AE serve as a cathode and the transparent electrode Yt (thescan electrode YE) serve as an anode. In this case, from two transparentelectrodes Yt adjacent to each other with the address electrode AE inbetween, electric fields E1 and E2 are generated in the addresselectrode AE. Here, the electric field E1 is generated between theaddress electrode AE and a transparent electrode Yt of the selectioncell C1 side which corresponds to the address electrode AE, and theelectric field E2 is generated between the address electrode AE and atransparent electrode Yt of the non-selection cell C1 side which doesnot correspond to the address electrode AE. In the example of thedrawing, since the distance between the transparent electrode Yt of thenon-selection cell C1 and the address electrode AE of the selection cellC1 is greater than the distance between the transparent electrode Yt ofthe selection cell C1 and the address electrode AE of the selection cellC1, the electric field E2 is weaker than the electric field E1.

Positive ions present in the discharge space DS of the selection cell C1are drawn to the address electrode AE, and collide with the protectivelayer PL on the address electrode AE. As a result, secondary electronsare emitted from the protective layer PL, whereby address dischargeoccurs efficiently. Moreover, even when positive ions present in thedischarge space DS of the non-selection cell C1 are drawn to the addresselectrode AE, the positive ions do not reach the protective layer PL onthe address electrode AE as a result of being obstructed by the barrierrib BR. As a result, no erroneous discharge occurs in the non-selectioncell C1.

That is, in this embodiment, when address discharge is made to occurbetween the address electrode AE and the transparent electrode Yt of theselection cell C1 (during an address period), it is possible to preventerroneous discharge from occurring in the non-selection cell C1 adjacentto the selection cell C1. Incidentally, since no discharge (erroneousdischarge) occurs in the non-selection cell C1, positive ions collidingwith the phosphors PHr, PHg, and PHb applied to the barrier ribs BR donot increase due to discharge. Therefore, the collision of the positiveions with the phosphors has no influence on deterioration of imagequality of the PDP 10.

Moreover, in this embodiment, by making the address electrode AE serveas a cathode and the transparent electrode Yt (the scan electrode YE)serve as an anode, positive ions are collided with the protective layerPL on the address electrode AE, and secondary electrons are emitted fromthe protective layer PL. Here, the protective layer PL on the addresselectrode AE deteriorates to a far lesser extent than the protectivelayer PL on the transparent electrodes Xt and Yt. This is because theprotective layer PL on the transparent electrodes Xt and Yt deterioratesgreatly at the time of sustain discharge. In this embodiment, since theprotective layer PL on the address electrode AE does not suffer muchdeterioration, it is possible to prevent deterioration ofcharacteristics such as discharge time lag in address discharge.

FIG. 5 shows an example of the configuration of a field FLD fordisplaying an image of one frame. One field FLD is 1/60 second (about16.7 ms) in length, and is made up of eight subfields SF (SF1-SF8), forexample. Each subfield SF is made up of a reset period RST, an addressperiod ADR, and a sustain period SUS. Incidentally, in this embodiment,an erase period during which discharge for reducing the wall charges ofonly a lit cell is made to occur (for example, FIG. 6( i), which will bedescribed later) is defined as being included in the sustain period SUS.Moreover, the erase period is sometimes defined separately from thesustain period SUS. Here, the wall charges are, for example, a positivecharge and a negative charge accumulated on the surface of theprotective layer PL shown in FIG. 2 in each cell, the protective layerPL formed of MgO or the like.

The length of the sustain period SUS differs according to each subfieldSF, and depends on the number of discharges (luminance) of a cell.Therefore, by changing the combination of the subfields SF to be lit, itis possible to display an image with a multiple gradation. In thisexample, the numbers of sustain discharges previously set for thesubfields SF1-8 are 4, 8, 16, 32, 64, 128, 256, and 512, respectively.As shown in FIG. 6, which will be described later, a cell dischargestwice in one discharge cycle CYC (star signs in the drawing).

FIG. 6 shows an example of discharge operation of the subfield SF shownin FIG. 5. A star sign in the drawing represents the occurrence ofdischarge.

First, during the reset period RST, a slowly increasing positive voltage(a slope pulse) is applied to the sustain electrode XE (the buselectrode Xb and the transparent electrode Xt), and a negative voltageVry1 (a first voltage) is applied to the scan electrode YE (the buselectrode Yb and the transparent electrode Yt) (FIG. 6( a)). Inaddition, the sustain electrode XE is maintained at a positive writevoltage, and a negative write voltage (a write slope pulse voltage WW)decreasing slowly from the voltage Vry1 to a voltage Vry2 (a secondvoltage) is applied to the scan electrode YE (FIG. 6( b)). This allowsnegative and positive wall charges to be accumulated in the sustainelectrode XE and the scan electrode YE, respectively, while preventingthe luminescence of the cell.

Next, a negative voltage Vx is applied to the sustain electrode XE, apositive adjusting voltage (an adjusting slope pulse voltage AW)increasing slowly from a voltage Vry3 (a third voltage) to a voltageVry4 (a fourth voltage) is applied to the scan electrode YE, and apositive voltage Vb is applied to the address electrode AE (FIG. 6( c)).This makes it possible to adjust the amounts of wall charges accumulatedin the sustain electrode XE, the scan electrode YE, and the addresselectrode AE. Incidentally, for example, the negative voltage Vx is avoltage higher than a voltage -Vs/2, the voltage Vry3 of the adjustingslope pulse voltage AW is a voltage equal to or higher than the voltageVry1, and the voltage Vry4 of the adjusting slope pulse voltage AW is avoltage higher than a voltage Vs/2. By making the voltage Vry4 higherthan the voltage Vs/2, in this embodiment, it is possible to preventerroneous discharge from occurring between the scan electrode YE and theaddress electrode AE during the sustain period SUS.

Moreover, since the positive voltage Vb is applied to the addresselectrode AE while the adjusting slope pulse voltage AW is being appliedto the scan electrode YE, an address pulse APL operating as a cathode,the address pulse APL of the address period ADR, may change to thenegative side with respect to the positive voltage Vb. That is, in thisembodiment, it is possible to apply the address pulse APL operating as acathode to the address electrode AE without using a negative voltagelower than a voltage GND. This makes it possible to simplify a design ofa driver circuit (for example, a driver ADRV shown in FIG. 7, which willbe described later) for applying a voltage to the address electrode AE.

During the address period ADR, the sustain electrode XE is maintained atthe negative voltage Vx, a positive non-selection voltage Vsc is appliedto the scan electrode YE, and the address electrode AE is maintained atthe positive voltage Vb (FIG. 6( d)). In addition, the sustain electrodeXE is maintained at the negative voltage Vx, a scan pulse SPL (a voltageVy) operating as an anode is applied to the scan electrode YE, and anaddress pulse APL (a voltage GND of a grounding conductor) operating asa cathode is applied to the address electrode AE corresponding to a cellto be lit (a selection cell) (FIG. 6( e)). For example, the scan pulseSPL operating as an anode is a positive pulse, and the voltage Vy of thescan pulse SPL is a voltage higher than the voltage Vs/2. Furthermore,the address pulse APL operating as a cathode is a negative pulse, forexample.

In the cell (the selection cell) selected by the scan pulse SPL and theaddress pulse APL, discharge (address discharge) temporarily occurs.That is, a voltage equal to or higher than a minimum voltage (a firingvoltage) making discharge occur is applied between the scan electrode YEand the address electrode AE, and a voltage lower than the firingvoltage is applied between the sustain electrode XE and the addresselectrode AE. This makes it possible to prevent erroneous discharge fromoccurring between the sustain electrode XE and the address electrode AEwhen address discharge is made to occur between the address electrode AEand the scan electrode YE.

Incidentally, in this embodiment, the voltage Vy of the scan pulse SPLis a voltage higher than the voltage Vry4. For example, the voltage Vyis about 10 V higher than the voltage Vry4. This makes it possible toreduce the amplitude (the voltage Vb—the voltage GND) of the addresspulse APL and make the driving force of a driver circuit (for example, adriver ADRV shown in FIG. 7, which will be described later) small, thedriver circuit for applying a voltage to the address electrode AE.Incidentally, the voltage difference between the voltage Vy and thevoltage Vb is smaller than the firing voltage between the addresselectrode AE and the scan electrode YE. This makes it possible toprevent erroneous discharge from occurring between the address electrodeAE maintained at the voltage Vb and the scan electrode YE to which thescan pulse SPL (the voltage Vy) has been applied.

Moreover, the sustain electrode XE becomes a cathode for the scanelectrode YE by the negative voltage Vx at the time of addressdischarge. The scan electrode YE becomes an anode for the sustainelectrode XE and the address electrode AE by the voltage Vy (the scanpulse SPL operating as an anode) at the time of address discharge. As aresult, in the cell selected by the address discharge, positive andnegative wall charges are accumulated in the sustain electrode XE andthe scan electrode YE, respectively. Furthermore, the address electrodeAE becomes a cathode for the scan electrode YE by the voltage GND (theaddress pulse APL operating as a cathode) of the grounding conductor,the voltage GND lower than the voltage Vy, at the time of addressdischarge.

As explained in FIG. 4 described above, since address discharge is madeto occur by making the address electrode AE of the selection cell C1serve as a cathode, it is possible to prevent positive ions present inthe discharge space DS of a non-selection cell C1 from colliding withthe protective layer PL, and thereby prevent erroneous discharge fromoccurring in the non-selection cell C1. On the other hand, when addressdischarge is made to occur by, for example, making the address electrodeAE serve as an anode and the transparent electrode Yt (the scanelectrode YE) serve as a cathode, electric fields (in a directionopposite to the electric field E1 and in a direction opposite to theelectric field E2, the electric fields E1 and E2 shown in FIG. 4described above) are generated from the address electrode AE in twotransparent electrodes Yt adjacent to each other with the addresselectrode AE in between. As a result, there is a possibility thatpositive ions present in the discharge space of the non-selection cellC1 are drawn to the transparent electrode Yt and collide with theprotective layer PL on the transparent electrode Yt. In this case, inthe non-selection cell C1, there is a possibility that secondaryelectrons are emitted from the protective layer PL on the transparentelectrode Yt and erroneous discharge occurs.

The second address pulse APL shown in the waveform of the addresselectrode AE is applied to select a cell in another display line (FIG.6( f)). Incidentally, when no scan pulse SPL is applied to the scanelectrode YE, a non-selection voltage Vsc lower than the voltage Vy andthe voltage Vry4 is applied to the scan electrode YE. That is, duringthe address period ADR, a predetermined voltage (a non-selection voltageVsc) lower than the voltage Vy is applied to the scan electrode YE towhich no scan pulse SPL is applied. As a result, in this embodiment, itis possible to reduce the amount of change in voltage (the voltageVy—the voltage Vsc) when a scan pulse SPL is applied, and make thedriving force of a driver circuit (for example, a driver YDRV shown inFIG. 7, which will be described later) small, the driver circuit forapplying a voltage to the scan electrode YE.

Incidentally, the voltage difference between the non-selection voltageVsc and the address pulse APL (the voltage GND) is smaller than thefiring voltage between the address electrode AE and the scan electrodeYE. For example, the non-selection voltage Vsc is smaller than a finalvoltage (the voltage difference between the voltage Vry4 and the voltageVb) between the scan electrode YE and the address electrode AE when theadjusting slope pulse voltage AW is applied to the scan electrode YE(FIG. 6( c)). This makes it possible to prevent erroneous discharge fromoccurring between the scan electrode YE maintained at the non-selectionvoltage Vsc and the address electrode AE when the address pulse APL forselecting a cell in another display line is applied to the addresselectrode AE (FIG. 6( f)).

During the sustain period SUS, in the beginning, a positive sustainpulse (a high-level voltage Vs/2) is applied to the sustain electrodeXE, a negative sustain pulse (a low-level voltage −Vs/2) is applied tothe scan electrode YE, and a voltage GND of the grounding conductor isapplied to the address electrode AE (FIG. 6( g)). Since positive andnegative wall charges have been accumulated in the sustain electrode XEand the scan electrode YE, respectively, in a cell (a cell to be lit)selected during the address period ADR, the voltage difference betweenthe sustain electrode XE and the scan electrode YE becomes greater thanthe voltage difference (the voltage Vs) between the positive andnegative sustain pulses. As a result, in the cell to be lit, the voltagedifference between the sustain electrode XE and the scan electrode YEbecomes greater than the firing voltage between the sustain electrode XEand the scan electrode YE, and discharge occurs between the sustainelectrode XE and the scan electrode YE.

In this embodiment, since it is possible to make discharge occur betweenthe sustain electrode XE and the scan electrode YE by the first sustainpulse, the sustain period SUS or the field FLD can be used effectively.Incidentally, in the cell (the cell to be lit) in which discharge hasoccurred, negative and positive wall charges are respectivelyaccumulated in the sustain electrode XE to which the positive sustainpulse has been applied and the scan electrode YE to which the negativesustain pulse has been applied.

Next, negative and positive sustain pulses are applied to the sustainelectrode XE and the scan electrode YE, respectively (FIG. 6( h)). Inthe cell (the cell to be lit) in which the discharge occurred in thesustain pulse shown in FIG. 6( g) which is immediately before thesustain pulse shown in FIG. 6( h), since the negative and positive wallcharges have been accumulated in the sustain electrode XE and the scanelectrode YE, respectively, discharge occurs between the sustainelectrode XE and the scan electrode YE. As a result, a discharge stateof the lit cell is maintained. Incidentally, in the cell in whichdischarge has occurred, positive and negative wall charges arerespectively accumulated in the sustain electrode XE to which thenegative sustain pulse has been applied and the scan electrode YE towhich the positive sustain pulse has been applied. As a result of thesustain pulses having different polarities being applied to the sustainelectrode XE and the scan electrode YE repeatedly (FIG. 6( g, h)),discharge of the lit cell during the sustain period SUS is repeatedlyperformed.

Finally, a positive erase pulse and a negative erase pulse are appliedto the sustain electrode XE and the scan electrode YE, respectively(FIG. 6( i)). As a result, discharge for reducing the wall charges ofonly a lit cell occurs. Since the difference in voltage value betweenthe positive and negative erase pulses is smaller than the difference involtage value between the positive and negative sustain pulses, theamount of wall charges is reduced. It is to be noted that, in a driverXDRV shown in FIG. 7 or the like, which will be described later, acircuit for applying a predetermined voltage (for example, a positiveerase pulse) to the sustain electrode XE during the reset period RST andthe sustain period SUS is not shown.

FIG. 7 shows an outline of the circuit unit 60 shown in FIG. 1. Thecircuit unit 60 includes an X driver XDRV applying a common pulse to thebus electrodes Xb, a Y driver YDRV selectively applying a pulse to thebus electrodes Yb, an address driver ADRV selectively applying a pulseto the address electrodes AE, a control unit CNT controlling theoperation of the drivers XDRV, YDRV, and ADRV, and a power supply unitPWR.

The drivers XDRV, YDRV, and ADRV operate as a driver unit driving thePDP 10. For example, the drivers XDRV, YDRV, and ADRV operate as adriver unit applying the voltages shown in FIG. 6 described above to theelectrodes XE, YE, and AE. The power supply unit PWR generatespower-supply voltages Vry1, Vry2, Vry3, Vry4, Vsc, Vy, Vs/2, −Vs/2, Vx,Vb, and the like, to be supplied to the drivers YDRV, XDRV, and ADRV.

Based on image data R0-7, G0-7, and B0-7, the control unit CNT selects asubfield to be used, and outputs control signals YCNT, XCNT, and ACNT tothe drivers YDRV, XDRV, and ADRV. In addition, by selecting a subfieldto be used for each cell C1 forming a pixel, an image with a multiplegradation is displayed. Incidentally, the image data R0-7, G0-7, andB0-7 is data of 8 bits for displaying red, green, and blue,respectively, and is sequentially input to the control unit CNT from atuner unit, not illustrated, or external input.

As described above, in this embodiment, during the address period ADR, ascan pulse SPL (a voltage Vy) operating as an anode is applied to thescan electrode YE, and an address pulse APL (a voltage GND of thegrounding conductor) operating as a cathode is applied to the addresselectrode AE corresponding to a cell to be lit (a selection cell). As aresult, in the selection cell, secondary electrons are emitted from theprotective layer PL, and address discharge occurs. In a non-selectioncell, since no secondary electrons are emitted from the protective layerPL, no discharge (erroneous discharge) occurs. That is, in thisembodiment, it is possible to prevent erroneous discharge.

Moreover, during the reset period RST, a slowly decreasing negativewrite slope pulse voltage WW is applied to the scan electrode YE, andthereafter a slowly increasing positive adjusting slope pulse voltage AWis applied to the scan electrode YE. As a result, in this embodiment, itis possible to accumulate negative and positive wall charges in thesustain electrode XE and the scan electrode YE, respectively, during thereset period RST while preventing the luminescence of the cell, andequalize the wall charges of all the cells C1.

Incidentally, the voltage value (the voltage Vy) of the scan pulse SPLis higher than the voltage Vry4. As a result, in this embodiment, it ispossible to reduce the amplitude (the voltage Vb—the voltage GND) of theaddress pulse APL, and make the driving force of the driver ADRV shownin FIG. 7, for example, small.

Furthermore, during the address period ADR, a non-selection voltage Vsclower than the voltage Vy is applied to the scan electrode YE to whichno scan pulse SPL is applied. As a result, in this embodiment, it ispossible to reduce the amount of change in voltage (the voltage Vy—thevoltage Vsc) when the scan pulse SPL is applied, and make the drivingforce of the driver YDRV shown in FIG. 7, for example, small.

Moreover, at the outset of the sustain period SUS, positive and negativesustain pulses are applied to the sustain electrode XE and the scanelectrode YE, respectively. As a result, in this embodiment, it ispossible to make discharge occur between the sustain electrode XE andthe scan electrode YE by the first sustain pulse, and use the sustainperiod SUS or the field FLD effectively.

Incidentally, in the embodiment described above, an example in which onepixel is made up of three cells (red (R), green (G), and blue (B)) hasbeen described. The present invention, however, is not limited to suchan embodiment. For example, one pixel may be made up of four or morecells. Alternatively, one pixel may be made up of cells generating acolor other than red (R), green (G), and blue (B), or one pixel mayinclude a cell generating a color other than red (R), green (G), andblue (B).

In the embodiment described above, an example in which the voltage value(the voltage Vy) of the scan pulse SPL is higher than the voltage Vry4has been described. The present invention, however, is not limited tosuch an embodiment. For example, the voltage value (the voltage Vy) ofthe scan pulse SPL may have the same voltage value as the voltage Vry4.Also in this case, it is possible to prevent erroneous discharge duringthe address period ADR.

In the embodiment described above, an example in which the non-selectionvoltage Vsc lower than the voltage Vy is applied, during the addressperiod ADR, to the scan electrode YE to which no scan pulse SPL isapplied has been described. The present invention, however, is notlimited to such an embodiment. For example, no non-selection voltage Vscmay be applied to the scan electrode YE, and the scan electrode YE maybe maintained at the voltage GND. Also in this case, it is possible toprevent erroneous discharge during the address period ADR.

In the embodiment described above, an example in which the positivevoltage Vb is applied to the address electrode AE while the adjustingslope pulse voltage AW is being applied to the scan electrode YE duringthe reset period RST has been described. The present invention, however,is not limited to such an embodiment. For example, the address electrodeAE may be maintained at the voltage GND during the reset period RST, andthe positive voltage Vb may be applied to the address electrode AEduring the address period ADR. Also in this case, it is possible toobtain the same effects as those obtained in the embodiment describedabove.

In the embodiment described above, an example in which positive andnegative sustain pulses (a high-level voltage Vs/2 and a low-levelvoltage −Vs/2) which are equal in amplitude (absolute value) from thevoltage GND of the grounding conductor are alternately applied to thesustain electrode XE and the scan electrode YE has been described. Thepresent invention, however, is not limited to such an embodiment. Forexample, a sustain pulse changing from the voltage GND (a low-levelvoltage) of the grounding conductor to the voltage Vs (a high-levelvoltage) may be alternately applied to the sustain electrode XE and thescan electrode YE. Also in this case, it is possible to obtain the sameeffects as those obtained in the embodiment described above.

In the embodiment described above, an example in which, in cells C1located on both sides of a particular address electrode AE, thetransparent electrodes Yt of the cells are disposed in positionsadjacent to each other with the address electrode in between has beendescribed. The present invention, however, is not limited to such anembodiment. For example, as shown in FIG. 8, in cells C1 located on bothsides of a particular address electrode AE, only the transparentelectrode Yt of one of the cells C1 may be disposed in a positionadjacent to the address electrode AE. A PDP of FIG. 8 differs from theembodiment described above in the arrangement of the transparentelectrodes Xt and Yt. Other configurations are the same as those of theembodiment described above. In the PDP of FIG. 8, the transparentelectrodes Xt and Yt face each other along the second direction, andsustain discharge occurs in that portion where the transparentelectrodes Xt and Yt face each other. Incidentally, regardless of thearrangement or shape of the transparent electrodes Xt and Yt, thepresent invention can be applied to a PDP having three electrodes (asustain electrode XE, a scan electrode YE, and an address electrode AE)on a glass base FS.

FIG. 9 shows the cross-section of the PDP 10 taken on the line A-A′ ofFIG. 8. In cells C1 (a selection cell C1 and a non-selection cell C1)located on both sides of a particular address electrode AE, an electricfield E1 is generated in the address electrode AE from the transparentelectrode Yt of one cell C1 (the selection cell C1), and an electricfield E2 is generated in the address electrode AE from the transparentelectrode Yt of the other cell C1 (the non-selection cell C1). Thedifference between the distance between the transparent electrode Yt ofthe non-selection cell C1 and the address electrode AE of the selectioncell C1 and the distance between the transparent electrode Yt of theselection cell C1 and the address electrode AE of the selection cell C1is greater than that of the embodiment described above. As a result, theelectric field E2 is still weaker than the electric field E1. Therefore,in the non-selection cell C1, the amount of positive ions colliding withthe phosphors PHr, PHg, and PHb applied to the barrier ribs BR is lessthan that of the embodiment described above. Also in this case, it ispossible to obtain the same effects as those obtained in the embodimentdescribed above.

In the embodiment described above, an example in which the addresselectrode AE and the dielectric layer DL1 are directly covered with theprotective layer PL has been described. The present invention, however,is not limited to such an embodiment. For example, as shown in FIG. 10,the address electrode AE and the dielectric layer DL1 may be coveredwith the protective layer PL with a dielectric layer DL2 interposedbetween them and the protective layer PL. FIG. 10 corresponds to thecross-section of the PDP 10 taken on the line A-A′ of FIG. 3. The PDP ofFIG. 10 is configured by adding the dielectric layer DL2 to theembodiment described above. Other configurations are the same as thoseof the embodiment described above. The dielectric layer DL2 is providedon the dielectric layer DL1, and covers the address electrode AE. Inaddition, the surface of the dielectric layer DL2 is covered with theprotective layer PL. Therefore, in the PDP of FIG. 10, on the glass baseFS, the sustain electrode XE and the scan electrode YE formed parallelto each other, the dielectric layer DL1, the address electrode AEextending in the orthogonal direction of the sustain electrode XE, andthe protective layer PL are sequentially stacked. Also in this case, itis possible to obtain the same effects as those obtained in theembodiment described above.

In the embodiment described above, an example in which the barrier ribsBR are disposed only in positions facing the address electrodes AE hasbeen described. The present invention, however, is not limited to suchan embodiment. For example, a barrier rib extending in the verticaldirection of the address electrode AE (the first direction D1 shown inFIG. 2 described above) may be provided on the glass base RS. In thiscase, for example, the barrier ribs extending in the first direction D1are disposed in positions facing the bus electrodes Xb and Yb, and areformed so as to be lower than the barrier ribs BR. This makes itpossible to set the discharge space DS of the assembled PDP 10 in avacuum state by means of an exhaust space ES without being blocked bythe barrier ribs extending in the first direction D1, and encapsulatedischarge gas in the discharge space DS. Also in this case, it ispossible to obtain the same effects as those obtained in the embodimentdescribed above.

Although the present invention has been described in detail, it is to beunderstood that the embodiment described above and the modified examplethereof are by way of illustration and example only and are not to betaken by way of limitation. Obviously, various modifications arepossible within the scope of the present invention.

The many features and advantages of the embodiment are apparent from thedetailed specification and, thus, it is intended by the appended claimsto cover all such features and advantages of the embodiment that fallwithin the true spirit and scope thereof. Further, since numerousmodifications and changes will readily occur to those skilled in theart, it is not desired to limit the inventive embodiment to exactconstruction and operation illustrated and described, and accordinglyall suitable modifications and equivalents may be resorted to, fallingwithin the scope thereof.

1. A driving method of a plasma display panel which includes: a firstplate on which a sustain electrode and a scan electrode being adjacentto each other and plurally disposed, a dielectric layer, an addresselectrode extending in a direction intersecting with the sustainelectrode, and a protective layer are sequentially stacked; and abarrier rib which is formed on a second plate disposed to face the firstplate via a discharge space and which extends in the directionintersecting with the sustain electrode, in which one edge part of theaddress electrode lies on the barrier rib and the other edge part of theaddress electrode lies on the discharge space, wherein one field fordisplaying one frame includes a plurality of subfields each having anaddress period, the driving method comprising the operation of applyinga scan pulse operating as an anode to the scan electrode and applying anaddress pulse operating as a cathode to the address electrode bothduring the address period.
 2. The driving method of the plasma displaypanel according to claim 1, wherein at least one of the subfields has areset period before the address period, and the driving method furtherincludes the operation of applying an adjusting slope pulse voltage tothe scan electrode after applying a write slope pulse voltage to thescan electrode during the reset period, in which the adjusting slopepulse voltage gradually increases from a third voltage not lower than afirst voltage to a fourth voltage and the write slope pulse voltagegradually decreases from the first voltage to a second voltage.
 3. Thedriving method of the plasma display panel according to claim 2, whereina voltage value of the scan pulse is higher than the fourth voltage. 4.The driving method of the plasma display panel according to claim 1,further comprising the operation of applying a predetermined voltagelower than a voltage value of the scan pulse to the scan electrode towhich the scan pulse is not applied, during the address period.
 5. Thedriving method of the plasma display panel according to claim 1, whereinthe subfields each have a sustain period during which a sustaindischarge is generated between the sustain electrode and the scanelectrode repeatedly, after the address period, and the driving methodfurther includes the operation of applying a high-level voltage to thesustain electrode and applying a low-level voltage to the scan electrodeat an outset of the sustain period, and applying alternately thehigh-level voltage and the low-level voltage to the sustain electrodeand the scan electrode, respectively, during the sustain period.
 6. Aplasma display device comprising: a plasma display panel; and a driverunit driving the plasma display panel, wherein the plasma display panelincludes: a first plate on which a sustain electrode and a scanelectrode being adjacent to each other and plurally disposed, adielectric layer, an address electrode extending in a directionintersecting with the sustain electrode, and a protective layer aresequentially stacked; a second plate disposed to face the first platevia a discharge space; and a barrier rib formed on the second plate andextending in the direction intersecting with the sustain electrode,wherein: one edge part of the address electrode lies on the barrier riband the other edge part of the address electrode lies on the dischargespace; one field for displaying one frame includes a plurality ofsubfields each having an address period; and the driver unit applies ascan pulse operating as an anode to the scan electrode and applies anaddress pulse operating as a cathode to the address electrode bothduring the address period.
 7. The plasma display device according toclaim 6, wherein at least one of the subfields has a reset period beforethe address period, and the driver unit applies an adjusting slope pulsevoltage to the scan electrode after applying a write slope pulse voltageto the scan electrode during the reset period, in which the adjustingslope pulse voltage gradually increases from a third voltage not lowerthan a first voltage to a fourth voltage and the write slope pulsevoltage gradually decreases from the first voltage to a second voltage.8. The plasma display device according to claim 7, wherein a voltagevalue of the scan pulse is higher than the fourth voltage.
 9. The plasmadisplay device according to claim 6, wherein the driver unit applies apredetermined voltage lower than a voltage value of the scan pulse tothe scan electrode to which the scan pulse is not applied, during theaddress period.
 10. The plasma display device according to claim 6,wherein the subfields each have a sustain period during which a sustaindischarge is generated between the sustain electrode and the scanelectrode repeatedly, after the address period, and the driver unitapplies a high-level voltage to the sustain electrode and applies alow-level voltage to the scan electrode at an outset of the sustainperiod, and alternately applies the high-level voltage and the low-levelvoltage to the sustain electrode and the scan electrode, respectively,during the sustain period.